Purpose Behavioral evaluation of language development is an important index for the usefulness of cochlear implantation. However, it could not apply to infants and very young children. It is useful to adopt an objective measure to examine speech discrimination in this population. Thus, the current study aimed to predict the different behavioral language performance (good versus poor) in cochlear implant (CI) recipients through the auditory cortical assessment of speech discrimination with mismatch negativity (MMN). Methods The study comprised 40 CI children who were divided into two groups according to their behavioral language evaluation outcomes: 20 good and 20 poor CI performers. They were age, gender, and socioeconomically matched. The MMN was examined and compared between both groups with finding out the relationship between MMN and different variables. Results MMN existed in all good performers and 87.5% of the poor performers. There were significantly shorter latency, larger amplitude, and a larger area of MMN in the good performers. The MMN results correlated with a significant predictive effect on the behavioral measures of language evaluation. Conclusion The MMN is a clinically applicable objective measure of speech discrimination proficiency. Hence, it could be useful in CI programming and auditory cortical monitoring during rehabilitation.